class_docstr: CelebA-HQ dataset, downsampled as 128x128.
code: def generate_data(self, data_dir, tmp_dir, task_id=-1):
      raise NotImplementedError(
          "Data preprocessing for CelebA-HQ is not "
          "currently available. Please follow the steps "
          "in https://github.com/tkarras/progressive_growin"
          "g_of_gans."
      )
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import os
  from tensor2tensor.data_generators import image_utils
  from tensor2tensor.data_generators import problem
  from tensor2tensor.layers import modalities
  from tensor2tensor.utils import metrics
  from tensor2tensor.utils import registry
  import tensorflow.compat.v1
  from tensorflow.compat.v1 import estimator
label_desc: Use image node_id 4 for calling the ImageCelebahq128 obj's underlying member method code with example usage: obj.generate_data(data_dir, tmp_dir, task_id) without return types